Apparatus for reducing the resistance of a ship hull



United States Patent Arthur Ernest Ruona Fairfax, Minnesota 55332 [21] App]. No. 756,829

[22] Filed Sept. 3, 1968 [4S] Patented Oct. 20, 1970 [72] Inventor [54] APPARATUS FOR REDUCING THE RESISTANCE OF A SHIP HULL v 2 Claims, 6 Drawing Figs.

[52] 1.1.8. Cl 114/67 [51] -lnt.Cl 1363b 1/34 I [50] Field ofSearch 114/671,

[56] References Cited UNITED STATES PATENTS 40,393 10/1863 Briggs 1 15/15X 312,500 2/1885 Owen 1 14/67 FOREIGN PATENTS 7,585 5/1896 Sweden 115/15 Primary Examiner-Andrew H. Farrell Attorney Merchant and Gould ABSTRACT: An aspirator affixed to a ship hull constructed so that water flowing therethrough creates a vacuum in a conduit communicating with the atmosphere to draw air from the atmosphere and mix it with the water, which mixture of air and water is discharged along the surface of the hull beneath the water line to lower the resistance of the hull.

Patented Oct. 2% 19% I N VEN'TOR. I 14/2770!" 536/000 M? 4 0M ATTORNEYS APPARATUS FOR REDUCING THE RESISTANCE OF A SHIP HULL BACKGROUND OF THE INVENTION 1. Field of the Invention Ship hulls traveling through the water have a definite resistance because of the tendency of the water to adhere to the sides of the hull. This resistance greatly increases the power required to drive the ship. Further, because of the resistance there is a tendency for water to be dragged with the ship whereby a large wake is created. Because of this wake ships must limit their speeds in certain areas.

2. Description of the Prior Art I In the prior art many devices have been designed whereby air under pressure is supplied to devices mounted below the water line so that the resistance can be reduced by an air and water mixture. In all of these devices the air is supplied by means of pumps which greatly increase the cost of the devices as well as the expense of running the same. In some prior art devices water is simply directed through a device and egresses through jets at the rear thereof, under natural pressure of the ships movement or additional pressure supplied by pumps and the like, to increase the turbulence of the water adjacent the ships bull in an attempt to reduce the resistance of the hull. These prior art devices are also extremely expensive to construct and operate. In all of these prior art devices the additional moving parts, such as pumps and the like, greatly reduce the reliability of the devices.

SUMMARY OF THE INVENTION The present invention pertains to apparatus for reducing the resistance of a ship hull to movement through the water including an aspirator affixed to the ships hull having a water inlet, a gas inlet in communication with the atmosphere and an outlet for mixed gas and water directed rearwardly adjacent the ship's hull.

It is an object of the present invention to provide new and improved apparatus for reducing the resistance of a ship hull to movement through the water.

It is a further object of the present invention to provide an apparatus including an aspirator utilizing the natural flow of water therethrough to draw air from the atmosphere and mix it with the water to reduce the resistance of the ship's hull.

It is a further object of the present invention to provide apparatus for mixing air and water and directing it along the ships hull, which apparatus has no moving parts.

It is a further object of the present invention to provide an aspirator the gas inlet of which is in communication with a compartment of the ship, said compartment being in communication with the atmosphere, to supply a constant flow of fresh air therethrough.

These and other objects of this invention will become apparent to those skilled in the art upon consideration of the accompanying specification, claims, and drawings.

BRIEF DESCRIPTION OF THE DRAWINGS Referring to the drawings, wherein like characters indicate like parts throughout the FIGS;

FIG. 1 is a viewin side elevation of a ships hull with the present apparatus operatively attached thereto;

FIG. 2 is a view in bottom plan of the ships hull and attached apparatus as seen in FIG. 1;

FIG. 3 is an enlarged sectional view as seen from the line 3-3 in FIG. 2;

FIG. 4 is a view as seen from the left end of FIG. 3, portions thereof broken away and shown in section;

FIG. 5 is a view as seen from the right end of FIG. 3, portions thereof broken away and shown in section; and

FIG. 6 is a modification ofthe hull shown in FIG. 1 whereby ventilation of a compartment is achieved.

DESCRIPTION OF THE PREFERRED EMBODIMENTS In the FIGS. the numeral 10 generally designates a ship hull having a bow II, a stern I2, and the usual screw or propeller driving mechanism 13. The various superstructure and other apparatus generally affixed to the hull 10 are not illustrated in detail in the FIGS. because they do not form a portion of this invention. Further, it should be understood that the present apparatus might be utilized on substantially any ship hull l0 and, although no experimentation has been performed on smaller boats, certain embodiments of the invention might be utilized thereon.

The present apparatus generally designated 20 includes a conduit 21 having one end 22 in communication with the atmosphere above the deck of the ship hull 10 and the other end extending through the ship hull 10 below the water line, indicated by dotted line 23, generally forwardly of the bow II. and an aspirator 25 affixed to the forward end of the conduit 21. In this preferred embodiment the aspirator 25 is mounted adjacent the bow II to aid in breaking the water prior to contact with the bow II, which breaking tends to reduce the water pushed by the bow 11, or bow swell, thereby reducing the wake of the ship hull It). It should be understood, however, that one or more aspirators 25 might be mounted at different locations along the ship hull I0 to increase the amount of air mixed with the water or to decrease the overall size of a single apparatus by distributing the operations among a number of smaller apparatus.

The aspirator 25 includes an outer generally bulb-shaped housing 26 having a water inlet 27 in the front end thereof with the smaller or tapered end 28 open. The water inlet 27 and the tapered end 28 are oppositely directed so that water entering the inlet 27 can flow freely from the tapered end 28 with little change in direction. The aspirator 25 further includes a cap 30 having an elongated tubular body with one end thereof closed by a generally hemispherical portion.

The cap 30 is fitted generally coaxially over the forwardly extending end of the conduit 21 with the closed end of the cap 30 adjacent the open end of the conduit 21 and the body of the cap 30 extending generally parallel with the conduit 21 and spaced radially outwardly therefrom. Thus, gas leaving the conduit 21 is turned and directed rearwardly toward the ship hull 110.

The cap 30 is in turn mounted generally coaxially within the housing 26 so that the closed end thereof is adjacent the water inlet 27 and directs water outwardly therearound and the open end of the cap 30 is adjacent the open tapered end 28 of the housing 26. Thus, water entering the water inlet 27 is directed around the cap 30 within the housing 26 and out the tapered end 28. Because the housing 26 is generally bulb-shaped the distance between the housing 26 and the cap 30 gradually diminishes toward the tapered end 28. As water enters the water inlet 27 and flows toward the tapered end 28 the area in which the water is flowing decreases so that the velocity of the water must increase, which increased velocity produces a partial vacuum at the open end of the cap 30 thereby drawing air through the conduit 21. The air and water mix at the tapered end 28 and are ejected along the ship hull 10 to reduce the resistance thereof. In the present embodiment the cap 30 and housing 26 are attached to the conduit 21 by means of a plurality of radially outwardly extending struts 35 adjacent the tapered end 28 and a plurality of struts 36 which extend generally forwardly and outwardly from the conduit 21 through the cap 30 to the housing 26. It should be understood that a variety of aspirators 25 as well as a variety of means for mounting the aspirators 25 might be provided by those skilled in the art and the present embodiment is utilized only as an example to illustrate the functions of the present invention.

In FIG. 6 a slightly different embodiment of the present apparatus is illustrated wherein the conduit 21 is in communication with a compartment 40 in the ship hull 10. The compartment 40 is in communication with the atmosphere through a second conduit 41 so that fresh air is constantly flowing through the compartment 40 when the ship hull is moving through the water. Thus, in addition to greatly reducing the resistance of the ship hull 10 to movement through the water, the present apparatus may be utilized to provide fresh air throughout various compartments located below the deck, which compartments would require fans or the like to provide fresh air if the present apparatus were not utilized.

Thus, apparatus is disclosed having no moving parts which is capable of greatly reducing the resistance of a ship hull to movement through the water. Further, the present apparatus can be mounted so as to reduce the bow swell by breaking the water prior to contact with the bow of the ship. In addition to the above the present apparatus is useful to supply fresh forced air throughout compartments of the ship which require a continuous supply of air while the ship is moving.

Iclaim:

1. Apparatusfor reducing the resistance of a ship hull to movement through the water comprising:

a. an aspirator having a generally bulb-shaped housing affixed to the ship hull adjacent the bow thereof for partially breaking the water prior to contact with the ship hull. said aspirator having a water inlet, a gas inlet. and a gas and water outlet directed oppositely of said water inlet;

b. said aspirator being positioned with said water inlet directed generally forwardly relative to the ship hull and said gas and water outlet directed generally rearwardly; and

c. means connecting said gas inlet in communication with a sufficient supply of gas to mix with the water and reduce the hull resistance.

2. Apparatus for reducing the resistance of a ship hull to movement through the water as set forth in claim I wherein the sufficient supply of gas in communication with the gas inlet of the apparatus includes at least a compartment in the ship hull and the aspirator further includes conduit communicating said compartment with the atmosphere to provide a constant flow of air therethrough. 

